A construction machine includes an engine, a hydraulic pump driven by power generated by the engine, a hydraulic cylinder driven by hydraulic oil discharged from the hydraulic pump, and a work machine operated by the hydraulic cylinder. A water cooling-type cooling device is used to cool the engine. An oil cooler is used to cool the hydraulic oil. The water cooling-type cooling device cools the engine by circulating cooling water in a circulation system including a jacket and a radiator provided in the engine. The hydraulic oil is cooled by being circulated in a circulation system including the oil cooler. The radiator and the oil cooler are cooled by a cooling fan. The radiator and the oil cooler are cooled by wind generated by the fan, so that the cooling water and the hydraulic oil are cooled.
An example of a fan drive device that drives a fan by oil pressure is disclosed in Patent Literature 1. In Patent Literature 1, the fan drive device includes a hydraulic pump driven by power generated by an engine and a hydraulic motor that rotates the fan on the basis of hydraulic oil supplied from the hydraulic pump.